(1) Field of the Invention
The present invention relates to the use of isolated and purified withanamides and withanolides in the treatment of various diseases, such as Alzheimer's Disease, depression, obesity and migraine headaches. The withanamides and withanolides were particularly isolated and purified from fruits of Withania somnifera. 
(2) Description of Related Art
Withania somnifera (L) Dunal of solanaceae, is an erect evergreen shrub distributed throughout the drier parts of India. W. somnifera, known as Aswagandha, is well known for its use in Ayurvedic medicine. The Aswagandha root extract was reported as a folk remedy for adenopathy, arthritis, asthma, hypertension, inflammations, and rheumatism (Thakur, R. S., et al., Major medicinal plants of India; Ed.; Central Institute of Medicinal and Aromatic Plants: Lucknow, India, 531 (1989)). The leaves of W. somnifera were also used as a cure for several illnesses including tumors, inflammations, conjunctivitis and tuberculosis (Thakur, R. S., et al., Major medicinal plants of India; Ed.; Central Institute of Medicinal and Aromatic Plants: Lucknow, India, 531 (1989)). Currently, powdered roots or root extract of this plant are used as a dietary supplement in the United States.
The major chemical constituents reported from W. somnifera are called withanolides. These compounds are structurally diverse steroidal compounds with an ergosterol skeleton in which C-22 and C-26 are oxidized to form a δ-lactone; (Ray, A. B., et al., Prog. Chem. Org. Nat. Prod. 63, 1-106 (1994)). The chemical investigations of the roots and leaves of W. somnifera resulted in the isolation and characterization of several withanolides (Matsuda, M., et al., Bioorg. Med. Chem. 9, 1499-1507 (2001)). The fruits of this plant are tiny orange berries and reported to contain saturated and unsaturated fatty acids (Stoller E. W., et al., Lloydia, 37, 309-312 (1974); Monika, P., et al., Asian J. Chem. 6, 442-444 (1994); and Monika, P., et al., Sci. Phys. Sci. 5, 81-83 (1993)). However, leaves and fruits are not fully investigated for biological activities. The withanolides are classified according to their structural skeleton (Ray, A. B., et al., Prog. Chem. Org. Nat. Prod. 63, 1-106 (1994)) and the structural variation is responsible for the wide array of pharmacological activities. Withanolides have been studied for their anti-inflammatory, antitumor, cytotoxic, immunomodulating activities and for the protection against CCl4-induced hepatotoxicity (Ray, A. B., et al., Prog. Chem. Org. Nat. Prod. 63, 1-106 (1994); and Anjaneyulu, A. S. R., et al., Studies in Natural Products Chemistry: Structure and Chemistry (Part F); Ed. Atta-ur-Rahman, Vol. 20, 135-261 (1998)). They were also reported to induce phase-II enzymes in animal models, which is considered to be one of the mechanisms in cancer chemoprevention (Misico, R. I., et al., J. Nat. Prod. 65, 677-680 (2002); and Su, B. N., et al., Tetrahedron 58, 3453-3466 (2002)).
The life-supporting oxygen becomes toxic to most aerobic organisms when exposed to greater concentrations. Reasons for this toxicity are due to the formation of superoxide (O2−), hydrogen peroxide (H2O2); and hydroxyl (—OH.) radicals during the conversion of oxygen to water in the mitochondria. The free radicals generated from environmental contaminants and by exogenous factors such as drugs, toxins and stress cause oxidative damage to biological macromolecular structure and function (Wickens, A. P., Respiration Physiology, 128 371-3891 (2001)). This will then lead to the progression of many disease processes including atherosclerosis, cardiovascular diseases and cancer. Several studies linked to the aging process to the generation of reactive oxygen and nitrogen (Vaya, J., et al., Curr. Med. Chem. Imm., Endoc. & Metab. Agents 1 99-117 (2001)). The oxidative stress also damages the pancreatic β-cell's function and results in diabetes (West, I. C., Diabet Med. 17 171-180 (2000)). The singlet oxygen reacts with polyunsaturated fatty acids to form lipid peroxides which in turn decompose to initiate the formation of mutagens. Therefore, natural products or chemicals with potential to scavenge singlet species can reduce biological disorders that limit the progression of various aging related diseases. Many epidemiological studies shows that diets rich in antioxidants play a major role in the prevention of heart disease, cancer, diabetes, and Alzheimer's disease (Temple, N. J., Nutr. Res. 20 449-459 and references cited therein (2000)).
Some of the pharmaceuticals prescribed for depression or anxiety contain natural antioxidants. Mixtures of ascorbic acid, pyridoxine, carotene, vitamin E, Zn, nicotinamide, and Se were effectively used to treat depression or anxiety (Horrobin, D. F., PCT Int. Appl. WO98-48788, A1 1998 1105 (1998)). Natural antioxidants are used as food additives to inhibit lipid peroxidation and to maintain the nutritional qualities of food. It is also known that antioxidants decrease the side effects of chemotherapy during cancer treatment (Conclin, K. A., Nut. Canc. 37 1-18 (2000)). The synthetic antioxidants used to prevent the lipid peroxidation in food are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), and tert-butylhydroquinone (TBHQ). However, synthetic antioxidants are considered to be potential carcinogens (Marchant, C. A., Env. Health Persp. Supp. 104 1065-1073 (1996)) and hence there is considerable interest in developing safe and natural antioxidants.